Field of the Invention
The present invention relates generally to gait assist devices.
Related Art
Asymmetry of gait refers to a difference in gait parameters between the left and right lower limbs, including both asymmetrical distribution of weight, as well as unequal time spent on the left and right feet during stance. Asymmetric gait is common in individuals with unilateral lower limb amputations, post cerebral accident victims, stroke victims, and lower limb orthopedic surgery patients. Asymmetric gait has been linked with chronic overloading in the non-amputated limb. Such overloading can occur because less time is often spent on the amputated leg and a shorter step length is often taken on the intact leg. Additionally, gait asymmetry has been shown to increase with walking speed which can account for greater loading of the joints in the intact limb of unilateral amputees.
This asymmetry of gait and subsequent overloading of the non-amputated limb has been associated with osteoarthritis in the knee of the non-amputated limb, which can have a profound impact on an individual's quality of life. Research suggests this higher prevalence of osteoarthritis may be due to the increased force in the intact leg which results from asymmetrical gait. A possible explanation for the asymmetric force is the lack of proprioceptive feedback provided through the prosthetic as compared to the normal biological ankle. Unfortunately, interventions to improve gait symmetry in the amputee population have historically been qualitative and have focused on descriptions of symptoms resulting from asymmetrical gait instead of possible preventive therapy or treatment.